1. Field of the Invention
The present invention relates to an apparatus which generates an abridged map which has been produced by simplifying a road map.
2. Description of Related Art
There is a known method for simplifying the shape of a road based upon map data for displaying a map. For example, with the apparatus disclosed in Japanese Patent laid-open application Publication No. 11-202762, the shape of the road is simplified by performing procedures such as straightening or orthogonalization or the like upon the links which specify the road shape in the map data, and by displaying only landmark information within a range which is regulated by a mask. A map which is more easily viewed than a normal map is provided by displaying an abridged map generated using the road shape which has been simplified in this manner.
However, with the apparatus disclosed in Japanese Patent laid-open application Publication No. 11-202762, the abridged map is generated by simplifying the road shapes by performing procedures such as straightening or orthogonalization or the like upon each of the links. However, when simplifying a road shape by this type of processing method, if an abridged map of a plurality of routes is generated, it may happen that the road shape is not simplified appropriately. For example, when simplifying the road shapes for a plurality of routes which are mutually adjoining, it may happen that these routes overlap one another upon the abridged map.